Vertical axis wind turbine with variable area

ABSTRACT

A vertical axis wind turbine with variable area. In accordance with an embodiment, the vertical axis wind turbine comprises a vertically-oriented central mast, and a plurality of vertically oriented multi-section blades that are arranged around and coupled to the central mast. Each blade includes an outer section, and an inner section that can be telescoped with the mast, and relative to the outer section, to change the effective length and surface area of the blade. In accordance with an embodiment multiple sections can be telescoped in such a fashion to vary the area of the blade. A pneumatic or other controller can raise and lower the central mast and effect a corresponding change in the overall area of the wind turbine. This allows the area to be increased for use with lower wind speeds; and reduced for use with higher wind speeds. Adjusting the area of the wind turbine allows for power generation over a wider range of wind speeds, and more control over the maximum power output of the turbine, including the ability to depower the turbine in very high wind speeds, and reduce the likelihood of damage.

CLAIM OF PRIORITY

This applicant claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 61/117,059, titled “SYSTEM FOR PROVIDING DYNAMIC PITCH CONTROL IN A WIND TURBINE”, filed Nov. 21, 2008; and U.S. Provisional Patent Application Ser. No. 61/117,061, titled “VERTICAL AXIS WIND TURBINE WITH VARIABLE AREA”, filed Nov. 21, 2008, each of which applications are herein incorporated by reference.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

FIELD OF INVENTION

The invention is generally related to wind turbines and other mechanical turbines and motors, and is particularly related to a vertical axis wind turbine with variable area.

BACKGROUND

Wind power is the conversion of wind energy into a useful form of energy, such as electricity, using a wind turbine. Large wind turbines, and groups of turbines referred to as wind farms, can be connected to the electrical grid, and their power output used to power whole communities. Smaller, individual wind turbines can be used to provide power to isolated locations, such as single household or farm. Wind energy is a plentiful, renewable, and clean energy source, and is an important step in eliminating dependence on fossil fuels, reducing greenhouse gas emissions, and providing an alternative and environmentally friendly energy source. Technologies that allow wind turbines to make more optimal use of available winds are of great interest in promoting the advance of wind power. This is the general area that embodiments of the invention are intended to address.

SUMMARY

Described herein is a vertical axis wind turbine with variable area. In accordance with an embodiment, the vertical axis wind turbine comprises a vertically-oriented central mast, and a plurality of vertically oriented multi-section blades that are arranged around and coupled to the central mast. Each blade includes an outer section, and an inner section that can be telescoped with the mast, and relative to the outer section, to change the effective length and surface area of the blade. In accordance with an embodiment multiple sections can be telescoped in such a fashion to vary the area of the blade. A pneumatic or other controller can raise and lower the central mast and effect a corresponding change in the overall area of the wind turbine. This allows the area to be increased for use with lower wind speeds; and reduced for use with higher wind speeds. Adjusting the area of the wind turbine allows for power generation over a wider range of wind speeds, and more control over the maximum power output of the turbine, including the ability to depower the turbine in very high wind speeds, and reduce the likelihood of damage.

BRIEF DESCRIPTION OF THE FIGURES:

FIG. 1 is an illustration of a system that uses a wind turbine for generation of power, in accordance with an embodiment.

FIG. 2 is an illustration of a vertical axis wind turbine in accordance with the prior art.

FIG. 3 is an illustration of a vertical axis wind turbine with variable area in accordance with an embodiment, showing both a side and a top view.

FIG. 4 is another illustration of a vertical axis wind turbine with variable area in accordance with an embodiment, showing the turbine in reduced area and increased area positions.

FIG. 5 is another illustration of a vertical axis wind turbine with variable area in accordance with an embodiment, showing an isometric view.

DETAILED DESCRIPTION:

Described herein is a vertical axis wind turbine with variable area. As described above, wind energy is a plentiful, renewable, and clean energy source, and is an important step in eliminating dependence on fossil fuels, reducing greenhouse gas emissions, and providing an alternative and environmentally friendly energy source. Technologies that allow wind turbines to make more optimal use of available winds are of great interest in promoting the advance of wind power. In accordance with an embodiment, the vertical axis wind turbine comprises a vertically-oriented central mast, and a plurality of vertically oriented multi-section blades that are arranged around and coupled to the central mast. Each blade includes an outer section, and an inner section that can be telescoped with the mast, and relative to the outer section, to change the effective length and surface area of the blade.

FIG. 1 is an illustration of a system 100 that uses a wind turbine for generation of power, in accordance with an embodiment. As shown in FIG. 1, in a typical wind power system, a turbine 102 is used to harness the power of the wind 106. Examples of wind turbines include horizontal-axis wind turbines (HAWT), which have the main rotor mast and electrical generator at the top of a tower, and must be pointed into the wind; and vertical-axis wind turbines (VAWT), which have the main rotor mast arranged vertically. The turbine is used to drive an electrical generator 108, and the electricity produced 110 can be stored, fed into an electrical grid, or otherwise provided to an electricity user 112.

FIG. 2 is an illustration of a vertical axis wind turbine in accordance with the prior art. As shown in FIG. 2, a typical VAWT 170 comprises a central axis 172, coupled to two or more blades 176. Incident wind causes the blades to turn about the central axis, and the rotation of the central axis can then be used to power an electric generator.

FIG. 3 is an illustration of a vertical axis wind turbine with variable area in accordance with an embodiment, showing both a side and a top view. As shown in FIG. 3, in the side view 220, the VAWT comprises a base 226, which in some embodiments can also include gearing, electrical, and pneumatic components, coupled to a vertically-oriented central mast 228. The base can also include an alternator for conversion of rotational speed into electricity.

A plurality of vertically oriented multi-section blades are arranged around and coupled to the central mast using struts or connectors 236. The struts can be designed to minimize drag loss at running speeds. Each blade includes an outer section 230, and an inner section 234 that can be telescoped relative to the outer section, to change the effective length and surface area of the blade.

Although the embodiment shown in FIG. 3 includes three blades in a variable H-rotor configuration, it will be evident that in other embodiments a different number of blades and configurations can be provided. Additionally, although the embodiment shown in FIG. 3 uses blades having two sections, including an inner section and an outer section, it will be evident that in other embodiments multiple sections can be telescoped in such a fashion to vary the area of the blade. In yet other embodiments the sections need not telescope within one another but rather can be mounted so as to slide relative to each other. In those embodiments that use a telescoping blade, since parts of these blades have to be larger than the rest, it is not possible to use the same blade chord as the baseline and oversized rotors for the entire variable area rotor. In accordance with an embodiment, the same blade extrusion can be used as the baseline for the part of the rotor with the smaller chord, and a larger shell for the outside part of each blade.

A pneumatic or other type of mechanical controller can be included within the central mast to raise and lower the mast, and effect a corresponding change in the overall area of the wind turbine. In accordance with an embodiment, the swept area ranges from 15 m² (lowered mast) to 25m² (raised mast). Other dimensions and areas can be used in other embodiments. This allows the area to be increased for use with lower wind speeds; and reduced for use with higher wind speeds. Adjusting the area of the wind turbine allows for power generation over a wider range of wind speeds, and more control over the maximum power output of the turbine, including the ability to depower the turbine in very high wind speeds, and reduce the likelihood of damage. FIG. 3 also shows a top view 224 of the VAWT in accordance with an embodiment, including the components as described above, and illustrating the telescopic nature of the blades in this particular embodiment.

FIG. 4 is another illustration of a vertical axis wind turbine with variable area in accordance with an embodiment, showing the turbine in reduced area and increased area positions. As shown in FIG. 4, in a first position 240, the central mast 228 is not extended. In this position, the blades connected 236 are similarly not extended, so that the area of each blade is equal to that of the outer section 230 (and perhaps a minimal amount of the inner section 234), and the total area of the turbine blade is comparatively reduced. As further shown in FIG. 4, in a second position 244, the central mast is extended, and in this position, the blades are similarly extended, so that the area of each blade is equal to that of the outer section 230 plus that of the newly exposed inner section 250. The total area of the turbine blade is comparatively increased.

FIG. 5 is another illustration of a vertical axis wind turbine with variable area in accordance with an embodiment, showing an isometric view. Again, as shown in FIG. 5, in a first position 240, the central mast 228 is not extended, the blades connected by 236 are similarly not extended, so that the area of each blade is equal to that of the outer section 230, and the total area of the turbine blade is comparatively reduced. In a second position 244, the central mast is extended, the blades are similarly extended, so that the area of each blade is equal to that of the outer section 230 plus that of the newly exposed inner section 250, and the total area of the turbine blade is comparatively increased.

The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art. Particularly, it will be evident that, although the embodiments described above generally illustrate the wind turbine oriented so that its mast is vertical, in accordance with other embodiments the wind turbine can be oriented so that its mast is horizontal, such as above the peak of a roof, or at the parapet of a flat roof. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalence. 

1. A vertical axis wind turbine with variable area, comprising: a base coupled to a vertically-oriented central mast that rotates; a plurality of vertically oriented multi-section blades that are arranged around and coupled to the central mast; and wherein each blade includes one or more sections that can be exposed to change the effective length or surface area of the blade and increase the effective area of the wind turbine.
 2. The vertical axis wind turbine of claim 1, wherein the base includes one or more of gearing, electrical, and pneumatic components, coupled to the central mast for generating electric power and one of raising and lowering the central mast.
 3. The vertical axis wind turbine of claim 1, wherein each of the blades includes an outer section, and an inner section that can be telescoped relative to the outer section, to change the effective length and surface area of the blade.
 4. The vertical axis wind turbine of claim 3, wherein for each blade the inner section can be telescoped within the outer section to reduce the blade area.
 5. The vertical axis wind turbine of claim 3, wherein the central mast can be telescoped in a vertical direction and which then causes the inner section of each blade to be telescoped relative to its outer section.
 6. The vertical axis wind turbine of claim 1, wherein the turbine uses two blades.
 7. The vertical axis wind turbine of claim 1, wherein the turbine uses more than two blades.
 8. The vertical axis wind turbine of claim 1, wherein each blade includes a plurality or multiple sections that can be telescoped to vary the area of the blade.
 9. The vertical axis wind turbine of claim 1, wherein the sections of each blade are mounted so as to slide relative to each other to increase or reduce the blade area.
 10. The vertical axis wind turbine of claim 1, wherein the effective area of the turbine blades is increased for use with lower wind speeds; and reduced for use with higher wind speeds.
 11. A vertical axis wind turbine with variable area, comprising: a base coupled to a vertically-oriented central mast that rotates, and wherein the base includes one or more of gearing, electrical, and pneumatic components, coupled to the central mast for generating electric power and one of raising and lowering the central mast; a plurality of vertically oriented multi-section blades that are arranged around and coupled to the central mast, wherein each of the blades includes an outer section, and an inner section that can be telescoped within the outer section, to change the effective length and surface area of the blade; wherein the central mast can be telescoped in a vertical direction and which then causes the inner section of each blade to be telescoped relative to its outer section; and wherein the effective area of the turbine blades is increased for use with lower wind speeds; and reduced for use with higher wind speeds.
 12. A wind turbine with variable area, comprising: a base coupled to a central mast that rotates; a plurality of multi-section blades that are arranged around and coupled to the central mast; and wherein each blade includes one or more sections that can be exposed to change the effective length or surface area of the blade and increase the effective area of the wind turbine, and wherein the central mast can be oriented one or more of vertically or horizontally.
 13. The wind turbine of claim 12, wherein the central mast is oriented vertically.
 14. The wind turbine of claim 12, wherein the central mast is oriented horizontally, for installation in locations such as above the peak of a roof, or at the parapet of a flat roof.
 15. The wind turbine of claim 12, wherein the base includes one or more of gearing, electrical, and pneumatic components, coupled to the central mast for generating electric power and one of raising and lowering the central mast.
 16. The wind turbine of claim 12, wherein each of the blades includes an outer section, and an inner section that can be telescoped relative to the outer section, to change the effective length and surface area of the blade.
 17. The wind turbine of claim 16, wherein for each blade the inner section can be telescoped within the outer section to reduce the blade area.
 18. The wind turbine of claim 16, wherein the central mast can be telescoped in a vertical direction and which then causes the inner section of each blade to be telescoped relative to its outer section.
 19. The wind turbine of claim 12, wherein the sections of each blade are mounted so as to slide relative to each other to increase or reduce the blade area.
 20. The wind turbine of claim 12, wherein the effective area of the turbine blades is increased for use with lower wind speeds; and reduced for use with higher wind speeds. 